Can someone point me to a solution to get LaTeX’s version of calligraphic font (if it is possible)? Perhaps a font feature option? I don’t know where to start if I were to try and search it myself.
The documentation for cal shows how to enable a font option (stylistic set) to get a different style, but I don’t think this will help you.
I think this is just New Computer Modern Math (used by Typst) being different from the default Latex font. If you do \usepackage{fontsetup} (the more recent way to setup fonts in Latex) it will also use New Computer Modern and you’ll get the same style as Typst.
To answer directly your question: you’d need to find a Truetype/OpenType font with this style for calligraphic letters. I don’t know if there’s one.
One possible font with this style of calligraphic letters would be this Garamond Math with stylistic set 3. To only use this font for those letters, you can define a custom function like this (using some weird hacks to circumvent a current limitation of Typst) :
#let cal(it) = math.class("normal", box({
show math.equation: set text(font: "Garamond-Math", stylistic-set: 3)
$#math.cal(it)$
}) + h(0pt))
The \mathcal font is not provided by amsmath. In User’s Guide for the amsmath Package:
The basic set of math font commands in LaTeX includes \mathbf, \mathrm, \mathcal, \mathsf, \mathtt, \mathit. Additional math alphabet commands such as \mathbb for blackboard bold, \mathfrak for Fraktur, and \mathscr for Euler script are available through the packages amsfonts and euscript (distributed separately).
The font you are using is the TFM font Computer Modern.